Indexing mechanism



y 1962 K. H. JENSEN 3,041,818

I INDEXING MECHANISM Filed July 16, 1958 I- yg INVENTOR Kaj H. Jensen ATTORNEYS United States Patent Gfitice Patented July 3, 1962 vania Filed July 16, 1958, Ser. No. 748,959 1 Claim. (Cl. 58-28) This invention relates to electric clocks and more particularly relates to an improved driving or indexing system for a battery driven electric clock of the type wherein the balance wheel serves both as the driving element and the regulating element.

U.S. patent to Koehler, No. 2,662,366, issued December 15, 1953, shows an electric clock of the foregoing type wherein the balance wheel is used to drive a conventional train. The present invention relates to an improvement in that type of clock utilizing an improved indexing or drive system which, in conjunction with an improved train, significantly reduces the number of bearings and wheels in the train with a concomitant reduction in the cost of the clock.

It is accordingly a primary object of the present invention to provide an irnproved battery driven electric clock.

It is another object of the invention to provide a battery driven electric clock having an improved indexing or driving arrangement.

It is another object of the invention to provide a battery operated electric clock having an improved and unique indexing arrangement wherein the balance or drive staff is mounted at right angles to the axes of the shafts and wheels in the train.

The foregoing and additional objects and advantages of the invention will become more apparent upon reference to the following specification and claim and appended drawings whereinz FIGURE 1 is a partial horizontal section of a clock constructed according to one embodiment of the invention;

FIGURE 2 is an exploded perspective view showing the index arrangement; and

FIGURE 3 is an illustration of the cooperation of the cam, spring and guide plate.

Referring to FIGURE 1, there is seen a U-shaped metal member indicated generally at which provides a pillar plate 12 and bridge 14. A center staff 16 is journaled in a bearing 18 in the bridge 14 and its other end is supported by the pillar plate 12 in a manner presently to be described in further detail. The center staff carries a fourth pinion 20 having an extended shoulder 22 which is pinned to the center staff.

A center arbor 24 is mounted over the center staff and is journaled at its left and right ends respectively on the shoulder 22 and on the center staff at 26. The center arbor 24 has a cannon pinion 28 rotatably mounted thereon and this cannon pinion is provided with an elongated barrel 30 which is received in the bearing in the pillar plate 12. A resilient spring 32 is mounted in a periph eral groove 34 in the center arbor 24 and frictionally engages the cannon pinion to provide a frictional drive between the cannon pinion and the center arbor.

The fourth pinion 20 drives a third wheel 36 which, with a third pinion 40, is journaled on a pin 38 mounted in the pillar plate 12. The third pinion 40 engages the cannon pinion 28 to establish a drive to the minute hand. The center arbor 24 has an integral pinion 42 formed integrally therewith and abutting the end of the barrel 30 of the cannon pinion 28.

An hour wheel 44 having an elongated barrel 46 is mounted over the center arbor and engages a pinion 48. The pinion 48 is formed integrally with a corresponding wheel 50 which is pivoted on the pin 38 and which engages the integral pinion 42. An hour hand 52 is attached to the barrel 46 on the hour wheel 44, a minute hand 54 is attached to the outer end of the center arbor 24 and a second hand 56 is attached to the end of the center stafi? 16. The center staff is driven by means of a fourth wheel 58.

A setting wheel 60 is mounted on a shaft 62 slidably and rotatably mounted in an aperture 64 in the pillar plate 12' and in an aperture 66 in the dial face 68. The

.shaft is urged outwardly by a spring attached to pillar plate 12 by a rivet 67.

The fourth wheel 58 is driven by the balance wheel as presently will be described in further detail, and drives the center arbor through the fourth pinion, third wheel, third pinion, cannon pinion, and flexible spring 32. The hour hand is, of course, driven by the pinion 42, wheel 50, pinion 48 and hour wheel 44. The movement may be set by depressing the shaft 62 to move the wheel 60 into engagement with the wheel 50, the spring 32 slipping to permitthe hands to be set.

The fourth wheel 58 is driven by means of an elongated spring 70 having one end 72 (FIGURE 2) friction mounted in a suitable hole in the pillar plate 12. The spring may be helically wound at 74 in order to provide adequate resilience. The spring 70 extends past the fourth wheel 58 and through a guide opening 76 in a guide plate 78. The guide plate 78 is formed of a rightangle plate 80 which extends up from the bridge 14. The plate 80 may be formed as an integral portion of the bridge 14, and struck outwardly therefrom, or may be formed separately and suitably secured to the bridge. The balance staff 82 is journalled in the plate 80 and carries a balance wheel 84.

Mounted on the balance staff 82 is a collar 86 carrying a generally helical cam 88. The outer end 90 of the spring 70 terminates short of the collar 86 but engages the cam 88 as seen in both FIGURES 1 and 2.

Intermediate the guide plate 78 and fourth wheel 58, the spring 70 carries a cylindrical contact 92. This con tact cooperates with a generally semi-cylindrical contact 94 carried by a flat spring 96 secured to an insulating block 98 as by a screw 100.

The fourth wheel 58 is provided with saw tooth shaped teeth 102 and the intermediate section of the spring 70 engages these teeth. A semi-cylindrical detent 104 is urged against the teeth 102 by means of a spring finger 106 secured to a bracket 108 (FIGURE 1) by means of a screw 110. The bracket 108 may be struck from the pillar plate or attached thereto in any suitable manner.

The guide hole 76 (FIGURE 2) in guide plate 78 has a substantially vertical drive side 112, an upwardly diagonally slanted return side 114, an inwardly and upwardly slanted return side 116 (FIGURE 3), and a diagonally upwardly extending slot 118. Referring to FIGURE 3, the cam 88 is shown diagrammatically to illustrate the operation of the indexing action. 7

The cam is shown at 88a moving to the left as the balance staff 82 rotates in a counter-clockwise direction in FIGURE 2. The spring 70 is shown at 70a in its normal rest position. Immediately beneath this depiction on the drawing, there is shown the position of the spring in the guide hole at that same moment. As the cam 88 moves to the left, it reaches the position shown at 8812 in FIGURE 3, at which time it has forced the spring 70 down to the position shown at 70b. This position is at the bottom of the guide hole 76 and the spring clears the bottom of the cam 88 at this time.

During the time that the spring 70 is forced downwardly from the position 70a to the position 70b, the intermediate portion thereof in engagement with the saw teeth 102 of the fourth wheel 58 forces that wheel to rotate clockwise a distance of one tooth. After the cam clears the spring immediately after leaving the position shown at 88b and 70b, the spring 70 moves upward due to its resilience and attempts to return to its -at-rest position as shown at 70a. As it rises, it is forced to the right, however, by the slope of the saw tooth and it rides along the side 114 of the guide hole 76. At the position 700 shown in the lower right corner of FIGURE 3, the spring clears the tooth and rides inwardly along the return surface 116 to return to the at-rest position 7 a. meantime, the balance stafl 82 has reached the end of its excursion to the left or counter-clockwise and commences to return to the right or in a clockwise direction. This is shown at 880 in FIGURE 3. The spring is in the at-rest position at 70c and is engaged by the upper surface of the cam. This forces the spring into the slot 118 and it clears the top of the cam to return to the at-restposition 70a in readiness for another cycle.

As, the spring 70 is forced down during the drive stroke, the cylindrical contact 92 engages the semi-cylindrical contact '94 and wipes across its surface to flex the spring 96. This establishes contact to the electro-magnetic driving mechanism and supplies the driving force to the clock, as is described in detail in the aforementioned Koehler patent. The connections to these contacts are made through the pillar plate and spring 96 which is insulated from the pillar plate. The contact system shown is particularly advantageous in that it provides a wiping contact which prevents oxidation and renders the contact self-cleaning.

It will be apparent from the foregoing that utilizing the improved index and drive arrangement of this in vention, a battery-driven electric clock may be produced using a smaller number of bearings and wheels than is conventional. This permits manufacture at a lower cost, diminishes the number of possible points of failure and reduces the wear and lubrication problems.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not re- In the 10 driving force to an electric timepiece comprising: a

5 embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

An indexing mechanism having a first and second contact adapted to be periodically closed for imparting a toothed wheel to be driven; an elongated spring member having one end fixedly mounted; said spring member extending past said toothed Wheel and in engagement therewith; a resilient member having one end fixedly mounted and the other end extending toward and in close proximity to said spring member; said first and second contacts being carried by said spring member and said resilient member, respectively; a guide plate positioned between the ends of said spring member and having an essentially elliptical guidehole therein through which said spring member passes; a balance staff; a cam on said balance staff for imparting essentially elliptical movement to the other end of said spring member; said cam engaging said other end of said spring member to cause said spring member to follow the essentially elliptical contour of said guidehole; whereby the essentially elliptical movement of said spring member causes said spring memberto drive said toothed wheel and to cause said first contact to periodically wipe across said second contact, thereby imparting the driving force to the electric timepiece.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Buechi: Great Britain (void specification), 504,365, published 1939, 

